Angle-of-Departure Measurement Using IQ Demodulation Phase
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Solution Overview
Problem
Current angle-of-departure measurement technologies face limitations in positioning accuracy due to signal gain or attenuation fluctuations and frequency or phase mismatches between local oscillators in transmitting and receiving terminals.
Innovation Solution
The solution involves calculating the angular position from a wireless transmitter based on the phase value of the ratio of I and Q signals demodulated in an IQ demodulator, and estimating the phase value for each transmitting antenna to reduce errors caused by signal gains, attenuations, and local oscillator frequency or phase differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radio frequency signals are transmitted from multiple transmitting antennas and received through a single receiving antenna, then angular position measurement can be performed, but positioning accuracy deteriorates due to signal gain or attenuation fluctuations and local oscillator frequency or phase mismatches
Solution Approach 1:
The patent extracts only the phase information from the received radio frequency signals, discarding the amplitude information that is affected by signal gain or attenuation fluctuations. By using only the phase component for angular position measurement, the system eliminates the harmful influence of amplitude variations and achieves accurate positioning despite signal strength changes.
Solution Approach 2:
The patent introduces an intermediary processing stage that separates the in-phase and quadrature components, then computes the phase angle from these components. This intermediary phase extraction process acts as a mediator that isolates the useful angular information from the harmful amplitude variations and local oscillator mismatches, enabling accurate measurement despite these interfering factors.
2Object-affected harmful factors
If phase information is extracted from received signals, then influence of signal gain or attenuation is eliminated, but errors due to local oscillator frequency or phase differences remain
Solution Approach 1:
The patent implements feedback mechanisms to compensate for local oscillator frequency and phase differences. The system continuously monitors and adjusts for these mismatches, using the feedback information to correct the phase measurements. This feedback approach eliminates the harmful effects of local oscillator inaccuracies while maintaining the benefits of phase-based measurement.
Solution Approach 2:
The patent changes the measurement parameter from amplitude-based to phase-based, which is inherently more robust to signal strength variations. By working with phase angles rather than signal amplitudes, the system transforms the measurement to be insensitive to gain and attenuation fluctuations, achieving improved precision despite remaining local oscillator errors.
3Measurement precision
If conventional angle-of-departure measurement technology is used, then system complexity is low, but positioning accuracy is limited due to signal gain fluctuations and local oscillator mismatches
Solution Approach 1:
The patent replaces conventional amplitude-based measurement methods with a phase-based digital signal processing approach. By substituting the measurement mechanism from amplitude detection to phase angle extraction and calculation, the system achieves higher precision without requiring complex hardware modifications. The improved accuracy is achieved through computational methods rather than increased system complexity.
Data Source
AI summary
Disclosed herein is to an angle-of-departure measurement technology that receives radio frequency signals transmitted from transmitting antennas and measures angular positions from the transmitting antennas with respect to the receiving antenna. A wireless receiver includes an IQ demodulator configured to perform IQ demodulation on signals received from the receiving antenna, a phase sample value can be calculated from a phase value of a ratio of I and Q signals, and a phase difference value between the plurality of transmitting antennas and the receiving antenna can be estimated from a phase sample value. An angular position of the wireless receiver can be calculated from the estimated phase difference value.